(1) Field of the Invention
This invention relates to detergent compositions which comprise specific types of N-acyl-N-hydroxyalkylglycines as a substrate and have good properties, and also to novel N-acyl-N-hydroxypropylglycines useful as the substrate for detergents.
(2) Description of the Prior Art
Detergents are required not only to have good detergent properties such as detergency and foaming power, but also to provide a low stimulus to the skin and the eye especially when they are used in direct contact with the skin as detergents for washing human bodies, e.g. shampoos, body shampoos and the like, detergents for tablewares and cooking utensils, and light detergents for wool.
These detergents contain surface active agents as a primary component. In most cases, anionic surface active agents are used for this purpose, including, for example, soaps (salts of fatty acids), linear alkylbenzenesulfonates (LAS), alkylsulfates (AS), polyoxyethylene alkyl ether sulfates (AES), alpha-olefinsulfonates (AOS), and the like. Although the anionic surface active agents exhibit high detergency, they are all stimulative to the skin and the mucous membrane of the eye, thus being not considered as the best surface active agent for use as a primary ingredient for the detergent. On the other hand, low stimulative surface active agents have been proposed including, for example, monoalkylphosphates, and N-acylamino acid salts such as N-acylglutamates, N-acyl-N-alkyl-beta-alanine salts, N-acyl-N-alkylglycine salts and the like. Although these salts are less stimulative, problems are involved in inherent detergent properties such as a hard water resistance, foaming and detergent properties and the like, economy and preparation.
With soaps (fatty acid salts), if divalent and higher valent metallic ions such as calcium ions are present, lime soap (scum) insoluble in water is formed. This is true of N-acylamino acid salts. The scum deposits on articles to be washed or a washtub at the time of washing and on a bath tub, a washing backet, tiles, the skin, the hair and the like at the time of bathing, thus causing the problems such as of the redeposition of dirt on the washings and the worsening of a bathing environment.
Accordingly, there is a demand for detergents which has a low stimulation, high detergency and a good hard water resistant and also for compounds exhibiting such characteristic properties as mentioned above.